6 Things You Need to Know About Tamiflu

En español l Quite suddenly, it seems, you feel just awful. Sore throat, cough, chills and body aches all but knock you off your feet. The flu comes on quickly, and this year, in particular, it's hitting older people hard. Hospitalizations for flu among people age 65 and older are spiking to levels not seen since the CDC began tracking the statistic five years ago.

Even those who've had a flu shot aren't necessarily immune; the U.S. Centers for Disease Control and Prevention (CDC) suggests this year's vaccine is 60 percent effective, perhaps much less so for seniors. Older people, along with small children, pregnant women and people with health problems such as lung or heart disease, are more likely to get very sick from the influenza virus, developing complications such as pneumonia. Those 65 or older account for some nine out of 10 flu-related deaths in the United States.Though most people recover from flu within a week or so with just rest and fluids, the CDC is urging those who fall seriously ill or are at risk for flu complications to seek prompt medical attention.

And for these patients, the agency says, doctors should not delay prescribing an antiviral drug — most often Tamiflu (oseltamivir) or less frequently an inhaled drug called zanamivir or Relenza. "For high-risk patients, antiviral treatment really can mean the difference between a milder illness and a stay in the hospital or in the intensive care unit or even death," CDC Director Tom Frieden, M.D., said in a briefing Jan. 18.

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Here, then, is the most up-to-date knowledge we have about Tamiflu and what the antiviral medication can and cannot do for you.

Q. Could Tamiflu help me feel better faster?

A. Yes. That's one thing just about everyone agrees — Tamiflu shortens flu symptoms by about a day. "If I woke up in the morning with aches, coughing, fever, I'd take Tamiflu if I could get it within 24 hours," says Mark Ebell, a family physician with the Department of Epidemiology and Biostatistics at the University of Georgia who has studied the drug's efficacy. "I'll feel better a day, maybe a day and a half, faster, and that's worth something to me. But I wouldn't take it if it were more than 24 hours after the start of my symptoms."

Q. Why is it important to take the drug soon after symptoms appear?

A. Tamiflu works by preventing infected cells from bursting, releasing flu virus that can infect nearby cells. This process has to be arrested early — most guidelines say within 48 hours of symptom onset — to make a difference. One large CDC analysis looking at pregnant women sick with the 2009 pandemic flu found that those who received antiviral treatment more than four days after falling ill were six times more likely to end up in intensive care than those who got the drug within two days.

A. Maybe. One review of clinical trials found insufficient evidence to assess that possibility. A recent analysis of 11 clinical trials by the University of Georgia's Ebell found a 1 percent reduction in pneumonia among flu sufferers treated with Tamiflu. The U.S. Food and Drug Administration (FDA), which regulates marketing claims based on its own review of clinical-trial evidence, does not allow Tamiflu's manufacturer Roche to assert that the medication reduces the rate of bacterial infections such as pneumonia.

Most of the clinical trials on Tamiflu have been in non-elderly, otherwise healthy adults.

But some observational research on high-risk patients is more positive. A recent analysis of 90 studies on patients hospitalized with the 2009 pandemic flu found that taking an antiviral (mostly Tamiflu) within two days was associated with a 65 percent drop in a patient's chance of dying and a substantially reduced risk of pneumonia.

Q. Can Tamiflu help prevent me from getting the flu after being exposed?

A. Probably, if taken within a couple of days of exposure. Tamiflu is approved by the FDA for this purpose. One controlled clinical trial published in 2001 found that Tamiflu was 89 percent effective at preventing flu in households where one member was already sick. The CDC does not recommend that everyone take antivirals preventively, but says the strategy can be considered for people at risk of developing complications if they catch the flu.

Q. Is Tamiflu safe?

A. First approved for adult use in 1999, Tamiflu has been used by tens of millions of people. The most common side effects are nausea and vomiting, each reported by about 10 percent of patients. FDA-approved labeling for the drug says that patients, especially kids, should be watched for delirium and abnormal behavior, an "uncommon" reaction that may be linked to the flu itself.

Q. I suspect I have the flu. Is there any reason to seek medical care besides getting an antiviral medicine?

A. Most people recover after six or seven days without treatment.

But those who are worried about the severity of their illness — are short of breath, dizzy, sick to their stomachs, say — should consult a doctor, says Michael Ison, M.D., an infectious diseases specialist with Northwestern University. So should people 65 or older who are at risk for serious problems from flu because of their age or who have an underlying health problem. "There are a lot of illnesses that look like flu," he says, such as bacterial pneumonia or another kind of virus. To find out for sure, go see your doctor.